Network systems that are constituted by a master device and a slave device are used as an industrial network system, and techniques relating to the network system are disclosed.
For example, JP 2014-119907A discloses a communication unit that is connected to a plurality of slave devices that operate based on setting information via a system bus so as to be able to communicate with the slave devices. If it is determined that the system has a configuration indicated by stored configuration information, the communication unit transmits setting information included in the configuration information to the slave devices. Therefore, JP 2014-119907A teaches that the communication unit can prevent an unexpected operation from occurring in the network system.
Furthermore, JP H9-128019A discloses a remote I/O system that is constituted by a remote master, and multiple IN slaves and OUT slaves that are connected to the remote master via a communication cable. In the remote I/O system, the remote master transmits OUT data simultaneously to the slaves, and the OUT slaves receive the OUT data at timings of their own nodes. On the other hand, the IN slaves sequentially transmit, based on the timing at which the OUT data is received, IN data at timings of their own nodes for each base idle time taking into consideration a frame length and a physical delay. The remote master receives the IN data from the IN slaves in a time slot based on the base idle time. Accordingly, JP H9-128019A teaches that overlap of the IN data due to a physical delay of a communication cable or the like does not occur.
JP 2014-119907A (published on Jun. 30, 2014), and JP H9-128019A (published on May 16, 1997) are examples of background art.